FreeBSD man pages : unlink (2)
UNLINK(2) FreeBSD System Calls Manual UNLINK(2)
unlink - remove directory entry
Standard C Library (libc, -lc)
unlink(const char *path);
The unlink() function removes the link named by path from its directory
and decrements the link count of the file which was referenced by the
link. If that decrement reduces the link count of the file to zero, and
no process has the file open, then all resources associated with the file
are reclaimed. If one or more process have the file open when the last
link is removed, the link is removed, but the removal of the file is
delayed until all references to it have been closed. path may not be a
The unlink() function returns the value 0 if successful; otherwise the
value -1 is returned and the global variable errno is set to indicate the
The unlink() succeeds unless:
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or
an entire path name exceeded 1023 characters.
[ENOENT] The named file does not exist.
[EACCES] Search permission is denied for a component of the
[EACCES] Write permission is denied on the directory containing
the link to be removed.
[ELOOP] Too many symbolic links were encountered in translat-
ing the pathname.
[EPERM] The named file is a directory.
[EPERM] The directory containing the file is marked sticky,
and neither the containing directory nor the file to
be removed are owned by the effective user ID.
[EBUSY] The entry to be unlinked is the mount point for a
mounted file system.
[EIO] An I/O error occurred while deleting the directory
entry or deallocating the inode.
[EROFS] The named file resides on a read-only file system.
[EFAULT] Path points outside the process's allocated address
close(2), link(2), rmdir(2), symlink(7)
An unlink() function call appeared in Version 6 AT&T UNIX.
The unlink() system call traditionally allows the super-user to unlink
directories which can damage the filesystem integrity. This implementa-
tion no longer permits it.
FreeBSD 4.8 June 4, 1993 FreeBSD 4.8